INTRODUCTION: We present a case of myoepithelial carcinoma of the lung with brain metastases. To our knowledge only 7 reported cases have been previously reported.
CASE PRESENTATION: This 38-y-old man presented to the Regional Medical Center at Memphis with complaints of headache, visual changes, unstable gait for 6 weeks and a 15 pound weight loss over 3 months. The patient was a 30 pack-year smoker with a prior history of emphysema and cocaine use. A head CT revealed three ring enhancing masses in the left parietal- occipital, right temporal and cerebellar areas. Chest X-ray and CT studies revealed a LUL mass. A retrospective review of films taken 3 years ago similarly revealed a subtle LUL nodule that had not been recognized at that time. The patient underwent resection of the left parieto-occipital lesion and later biopsy of the LUL. The histology specimens from both lung and brain were identical and revealed a malignant spindle cell malignancy. Given that both the lung and brain lesions were immunoreative for glial fibrillary acidic protein(GFAP), multifocal gliosarcoma with lung metastasis was initially considered. However, further workup revealed coexpression of smooth muscle actin (SMA), S- 100 protein, and various cytokeratins, including CK7. This distinctive immunoprofile established the diagnosis of myoepithelial carcinoma of the lung with brain metastasis.
DISCUSSIONS: Primary lung carcinomas showing features of salivary gland-type neoplasms are rare. Most are mucoepidermoid carcinomas and adenoid cystic carcinomas. Myoepithelial carcinoma of the lung is extremely rare, and in the WHO classification is classified under 'Others' among carcinomas of the salivary gland. A literature search revealed only 7 reported cases. The fact that tumor cells can be positive for GFAP is an underappreciated pitfall and led to the initial consideration of gliosarcoma or glioblastoma. Nevertheless, an expanded study confirmed the diagnosis of metastatic myoepithelial carcinoma due to the coexpression of additional myoepithelial markers (SMA, S-100),as well as CK7, the form of cytokeratin most commonly expressed in the lung.
CONCLUSION: This Unusal case of myoepithelial carcinoma of the lung is the 8th reported case to our knowledge. Very litttle is known about the treatment of metastatic myoepithelial carcinoma of the lung. Hopefully with more case reports our understanding will Improve of this unusal carcinoma of the lung.
DISCLOSURE: Yasser Aleech, None.